1. Field of the Invention
This invention relates to a method and a system for displaying an image on a display screen having a plurality of display rows, and more particularly to a method and a system for displaying an image wherein a boundary in a row direction between adjacent display areas on such display screen can be variably set for each display row.
2. Background Art
In an image display apparatus that is used for an information processing terminal, a plurality of display areas may be defined on the display screen, and an image may be displayed in each display area in order to utilize a limited display screen effectively.
For example, in Japanese Laid-open Patent Specification No. 92937/80, a display screen is constituted by defining in a row direction and in parallel a plurality of display areas having display length of m characters per a row, image information being stored in a screen memory having storage length of m characters per row in the order of display area and of row number, the contents of an address counter being transferred and stored into an auxiliary register when a character counter counts m, and the contents of the auxiliary register being set in the address counter to generate an address for reading the image information stored in the screen memory, thereby displaying an image in each display area.
In such conventional approach, the row display length of the display area is fixed to predetermined m characters for all display rows, and it is required to use specially a screen memory storing predetermined image information and having a storage length which is fixed to m.
Therefore, in the conventional approach, it is impossible to define at will a boundary in row direction between each adjacent display areas, to change the boundary for each display row, and to display image information from a usual refresh buffer memory through windowing.
An object of the invention is to provide an image display method ad its system wherein a boundary in row direction between each adjacent display areas on the display screen can be varied and defined for each display line.